The invention concerns a device for the automatic feeding of screws to a screw driver pin of a screwing mechanism, especially a rapid constructional screwing mechanism.
Rapid constructional screwing mechanisms are used for turning in screws, e.g., wooden screws in wood plates of wooden strips, especially for fastening chip plates on the floor, with which a single screw can be screwed in mechanically without a manual screw driver (actuating by hand). Such a rapid constructional screwing mechanism has a form similar to a hand-boring machine and exhibits an opening on the front end, into which a screw pin is inserted and can be fastened. The screw pin is so designed on its free end that a cross slot screw head, for example, can be fitted therein. During the turning-in of the screw, the drive of the rapid constructional screwing mechanism is operatively coupled with the screw pin jutting out of the rapid constructional screwing mechanism. After fastening of the screw, the coupling between the drive and the screw pin is released, due to which the screw pin becomes stationary, while the drive motor continues to turn. As mentioned, screws mostly employ cross slot screw heads.
In the past, the operator had to insert each screw indvidually on the free end of the screw pin (or screw bit). This was very time consuming and the number of screwed-in screws per unit of time was thus very small. To accelerate this procedure, devices were developed in which the individual screws were automatically conducted to the screwing mechanism pin. With such a design, the screws are set in a belt, which is wound around a drum, the latter fastened to a rapid constructional screwing mechanism. The belt is designed as a U-shaped plastic belt, the side ends of which are slotted, and into which slots the screws are inserted. Such insertion is made in such a way that each screw runs parallel to the belt strap and vertically to the sides between the latter. The belt is then conducted out of a storage place which is designed as a drum, to an automatic feed mechanism, in which the belt is laid and which is fastened on the rapid constructional screwing device. The mechanism has a primary part, which is set up directly on the flooring, for example with the screwing operation, and a second part which is movable relative to the first part. The second part is firmly connected with the rapid constructional screwing device and there is a spring between both parts which attempts to press the two parts apart. To initiate the turning-in of the screws, both parts are moved toward each other against the pressure of the springs, due to which the screw is turned downward into the flooring.
In general, with such mechanism, up to about 150 screws can be processed with one filling of the storage place. The operation of the mechanism is very simple, and the work, i.e., screwing-in of screws, can be carried out very rapidly. It is apparent that the equipping of the belt with individual screws increases the price of each screw processed at the end, if one takes the price of each individual screw as a basis. There is also the fact that the screws must be held individually in the belt because of the elasticity of it. Finally, the head of each screw must be pressed through the slots transverse to the shanks, which causes a bending up of the shanks. Naturally the belt is not stiff, due to which the danger exists that in rough operation or during transport, the screws can fall out onto the construction site, and thus are lost. If for example, during the transport on the screw belt or on the container in which the screw belt is transported, a heavy piece falls, then the screws held in the concerned belt are at least partially lost and must be individually screwed-in.
It is the object of the invention to avoid these disadvantages and to enable screws obtainable on the market packed in packages up to about 500 etc., to be capable of use immediately without the need for a belt or similar mechanism.